Changes In angulation and phalangeal length of fingers and thumbs following surgical treatment for congenital clinodactyly

INTRODUCTION: Congenital clinodactyly is a condition characterized by the deviation of a digit or digits in the coronal plane. Angulation is often due to the presence of a delta phalanx. There is a scarcity of long-term data regarding the results of surgical treatment for clinodactyly, particularly with respect to postoperative phalangeal growth and risk factors for recurrent deformity. METHODS: Our retrospective study involved the analysis of data from medical records of patients who had corrective surgery for congenital clinodactyly. We also measured radiographs to quantify the angle of deviation and the longitudinal lengths of the surgically corrected phalanx and corresponding metacarpal. Clinodactyly was defined as radiographic angulation of 10° or greater in the coronal plane. Recurrence was defined as a final angulation of 10° or greater as well as an increase of at least 10° compared with the immediate postoperative measurement. The primary ratio was defined as the ratio of the length of the primary ossification center of the surgically corrected phalanx to the length of the primary ossification center of the corresponding metacarpal. The secondary ratio was the ratio of the length of the primary and secondary ossification centers together of the corrected phalanx to those of the metacarpal. Comparisons were made between preoperative, postoperative, and most-recent follow-up values. Postoperative data was restricted to radiographs taken within three months after surgery. Final follow-up data was initially permitted if radiographs were taken at least one year after surgery. Additional analysis was performed of patients with a minimum of two years clinical and radiographic follow-up. RESULTS: There was a significant decrease in angulation with surgery and a significant increase in angulation postoperatively (p<0.001; p<0.01). Overall, the mean preoperative and final digital angulation was 40.4° and 17.4°, respectively, when a two-year minimum between the time of surgery and final follow-up measurements was implemented. This resulted in a significant average correction of 23.3° (p<0.001). The postoperative change in angulation was found to be significantly different depending on the surgical technique used. Digits corrected with reverse wedge osteotomies showed little to no change in angulation during the postoperative period. However, digits corrected with closing wedge osteotomies showed a significant increase in angulation between the immediate postoperative and final follow-up measurements (p=0.007). The rate of recurrence was 43.2% (95% CI: 28.7-58.9% with a one year minimum for follow-up; 95% CI: 27.5-60.4% with a two year minimum for follow-up). Postoperative changes in angulation or recurrence were not significantly associated with gender, patient age at the time of surgery, the type of digit corrected, coexisting congenital syndromes, or the presence of additional hand abnormalities. The primary ratio decreased significantly with surgery, from 0.35 preoperatively to 0.27 postoperatively (p=0.03). The primary ratio then increased significantly over time to 0.40 when there was a two-year minimum between the time of surgery and final follow-up. There was an insignificant change in primary ratio from immediately after surgery to final follow-up when data as early as one year postoperatively was included. The secondary ratio did not change significantly with surgery or during the postoperative period regardless of whether one or two-year time restrictions were in place. The mean secondary ratio was 0.29 before surgery, 0.25 immediately after surgery, and 0.33 at the time of final follow-up at least two years after surgery. CONCLUSIONS: Surgery to correct clinodactyly effectively decreases angulation of the digit, despite the risk of recurrent deformity over time. Our study did not identify any factors associated with recurrence. However, there was a significant difference in the change in angulation between the immediate postoperative and final follow-up measurements depending on the surgical technique used. Surgery to correct clinodactyly does not hinder postoperative growth of the corrected phalanx

The Effect of Print Angulation on the Accuracy and Precision of 3D-Printed Orthodontic Retainers

Purpose: The aims of this study were: 1) to compare the accuracy and precision of 3- dimensional (3D) printed retainers at various angulations, 2) to evaluate the effect of angulation on printing time and the amount of resin consumed. Methods: Using a stereolithography (SLA) 3D printer, a total of 60 clear retainers were printed at five angulations (n=12, each): 15, 30, 45, 60, and 90 degrees. Six retainers were printed each cycle at a random order for all print angulations as print 1 and print 2. Digital images of the original and printed retainers were superimposed. Discrepancies on eight landmarks were measured by two independent examiners. 0.25 mm was set as the clinically acceptable threshold to determine the accuracy of the retainers. Results: Deviations ranged from 0.074 mm to 0.225 mm from the reference retainer at the cusp tips and incisal edges at all angulations, falling within the threshold of clinical acceptance. Smooth surfaces ranged from 0.263 mm to 0.480 mm, falling beyond the level of clinical acceptance. Printing at 15 degrees was estimated to be the most time-efficient, while printing at 45 degrees was estimated to be the most cost-effective. Conclusions: 3D-printed retainers, using an SLA printer, were found to be accurate within 0.25 mm at all print angulations at the cusp tips and incisal edges when compared to the reference digital file. Smooth facial surfaces fell beyond of the level of clinical acceptability. Printing at 15 degrees was estimated to be the most time-efficient, while printing at 45 degrees was estimated to be the most cost-effective

Friction Testing of a New Ligature

Objective: To determine if American Orthodontics\u27 (AO) new, experimental ligature demonstrates less friction in vitro when compared to four other ligatures on the market. Methods: Four brackets were mounted on a custom metal fixture allowing an 0.018-in stainless steel wire attached to an opposite fixture with one bracket to be passively centered in the bracket slot. The wire was ligated to the bracket using one of five types of ligatures including the low friction test ligatures (AO), conventional ligatures (AO), Sili–TiesTM, Silicone Infused Ties (GAC), Synergy® Low-Friction Ligatures (RMO), and SuperSlick ligatures (TP Orthodontics). Resistance to sliding was measured over a 7 mm sliding distance using a universal testing machine (Instron) with a 50 Newton load cell and a crosshead speed of 5 mm/min. The initial resistance to sliding (static) was determined by the peak force needed to initiate movement and the kinetic resistance to sliding was taken as the force at 5 mm of wire/bracket sliding. Fifteen unique tests were run for each ligature group in both dry and wet (saliva soaked for 24 hours with one drop prior to testing) conditions. Results: In the dry state, the SuperSlick ligature demonstrated more static friction than all of the other ligatures, while SuperSlick and Sili–Ties demonstrated more kinetic friction than the AO conventional, AO experimental and Synergy ligatures. In the wet condition, SuperSlick and the AO experimental ligature demonstrated the least static friction, followed by the AO conventional and Sili–Ties. The most static friction was observed with the Synergy ligatures. In the wet condition, the SuperSlick, AO experimental and AO conventional exhibited less kinetic friction than the Sili-Ties and Synergy ligatures. Conclusions: AO\u27s experimental ligature exhibits less friction in the wet state than conventional ligatures, Sili–Ties and Synergy and is comparable to the SuperSlick ligature. These preliminary results suggest that the AO experimental ligature and the SuperSlick ligature create less friction, but direct conclusions regarding in vivo performance cannot be made and randomized controlled clinical trials are needed to determine if these ligatures have clinical significance in treatment efficiency

Fracture Resistance of Zirconia Oral Implants In Vitro: A Systematic Review and Meta-Analysis

Various protocols are available to preclinically assess the fracture resistance of zirconia oral implants. The objective of the present review was to determine the impact of different treatments (dynamic loading, hydrothermal aging) and implant features (e.g., material, design or manufacturing) on the fracture resistance of zirconia implants. An electronic screening of two databases (MEDLINE/Pubmed, Embase) was performed. Investigations including > 5 screw-shaped implants providing information to calculate the bending moment at the time point of static loading to fracture were considered. Data was extracted and meta-analyses were conducted using multilevel mixed-effects generalized linear models (GLMs). The Šidák method was used to correct for multiple testing. The initial search resulted in 1864 articles, and finally 19 investigations loading 731 zirconia implants to fracture were analyzed. In general, fracture resistance was affected by the implant design (1-piece > 2-piece, p = 0.004), material (alumina-toughened zirconia/ATZ > yttria-stabilized tetragonal zirconia polycrystal/Y-TZP, p = 0.002) and abutment preparation (untouched > modified/grinded, p < 0.001). In case of 2-piece implants, the amount of dynamic loading cycles prior to static loading (p < 0.001) or anatomical crown supply (p < 0.001) negatively affected the outcome. No impact was found for hydrothermal aging. Heterogeneous findings of the present review highlight the importance of thoroughly and individually evaluating the fracture resistance of every zirconia implant system prior to market release

Comparison of The Kois Dento-Facial Analyzer System with an Earbow for Mounting a Maxillary Cast

Statement of problem: The Kois Dento-Facial Analyzer System (KDFA) is used by clinicians to mount maxillary casts and evaluate and treat patients. Limited information is available for understanding whether the KDFA should be considered as an alternative to an earbow. Purpose: The purpose of this study was to evaluate maxillary casts mounted using the KDFA with casts mounted using Panadent\u27s Pana-Mount Facebow (PMF). Both articulation methods were compared against a lateral cephalometric radiograph. Material and methods: Fifteen dried human skulls were used. Lateral cephalometric radiographs and 2 maxillary impressions were made of each skull. One cast from each skull was mounted on an articulator by means of the KDFA and the other by using the PMF. A standardized photograph of each articulation was made, and the distance from the articular center to the incisal edge position and the occlusal plane angle were measured. The distance from condylar center to the incisal edge and the occlusal plane angle were measured from cephalometric radiographs. Finally, the 3-dimensional position of each articulation was determined with a Panadent CPI-III. A randomized complete block design analysis of variance (RCBD) and post hoc tests (Tukey-Kramer HSD) (α=.05) were used to evaluate the occlusal plane angle and axis-central incisor distance. A paired 2-sample t test for means (α=.05) was used to compare the X, Y, and Z distance at the right and left condyle. Results: The KDFA and PMF mounted the maxillary cast in a position that was not statistically different from the skull when comparing the occlusal plane angle (P=.165). Both the KDFA and the PMF located the maxillary central incisor edge position in a significantly different position compared with the skull (P=.001) but were not significantly different from each other. The 3-dimensional location of the maxillary casts varied at the condyles by approximately 9 to 10.3 mm. Conclusion: The KDFA mounted the maxillary cast in a position that was not statistically different from the PMF when comparing the incisal edge position and the occlusal plane angle. Both the KDFA and the PMF located the maxillary incisal edge position in a significantly different position compared with the anatomic position on dried human skulls

A Comparison of Three-Dimensional Printing Technologies on the Precision, Trueness, and Accuracy of Printed Retainers

Purpose: The aim of this study was to evaluate the differences in the precision, trueness, and accuracy of 3D printed orthodontic clear retainers produced using printer systems with various printing technologies. Methods: Retainers (n=15) were printed using four different 3D printers: a stereolithography (SLA) printer, two different digital light processing (DLP and cDLP) printers, and a polyjet photopolymer (PPP) printer. The 3D printed retainers were transformed into a digital file through a cone-beam computed tomography scan that was compared to the original image using a 3D superimposition analysis software. At previously chosen landmarks (R6, L6, R3, L3, R1, L1) retainers were compared to the reference model. The intercanine and the intermolar width measurements were also analyzed for deviations between the samples and the original file. A discrepancy up to 0.25mm was considered clinically acceptable. Precision of printers was evaluated on 5 randomly chosen samples. Trueness was determined by comparing the measurements on printed retainers to those on the original image file. Root mean square (RMS) and percent of points within the tolerance level (inTOL) were also calculated with respect to precision and trueness for each retainer. Samples were analyzed for intra-printer reliability (precision), and inter-printer trueness. Statistical significance was set at P\u3c0.05. Results: Interrater correlation coefficient indicated good agreement and all measurements were within 0.10mm at least 95% of the time. Statistically significant differences were found between printer types among each of the 6 landmarks and the arch widths. When evaluating inTOL and RMS, statistically significant differences in both median precision and trueness among each printer type were found. SLA and PPP printing technologies exhibited both excellent precision and trueness. Conclusion: Retainers fabricated by SLA, DLP, cDLP, and PPP technologies were shown to be clinically acceptable and accurate compared to the standard reference file. SLA and PPP printers showed greater accuracy, and the DLP and cDLP printers exhibited greater precision. The PPP printer had the most accurate intra-arch measurements followed by the SLA printer, and therefore, based on their high trueness and precision values, were deemed to be the most accurate overall

Accuracy of linear measurement using cone-beam computed tomography at different reconstruction angles

Purpose: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Materials and Methods: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., 0°), +10°, +12°, -12°, and -10° with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. Results: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of -12°, -0.66 to -0.11 at -10°, -0.51 to +0.19 at 0°, -0.64 to +0.08 at +10°, and -0.64 to +0.1 at +12°. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Conclusion: Changing the slice orientation in the range of -12°to +12°reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable. © 2014 by Korean Academy of Oral and Maxillofacial Radiology

Accuracy and precision of an intraoral scanner in complex prosthetic rehabilitations: an in vitro study

The main purpose of this study is to measure the accuracy and the precision of the intraoral optical scanner CS3500® (Carestream Dental LLC, Atlanta, USA) in complex clinical situations as full arch rehabilitations on impl ants. 50 scans of the acrylic resin model were performed by using CS3500® (Carestream Dental LLC, Atlanta, USA) scanner. Each scan was compared with the virtual model derived from scanning with the laboratory scanner Dscan3® (Enhanced Geometry Soluti on, Bologna, Italy) to measure a possible misalignment. The alignment error was found to be 79,6 ( ± 12,87)  m. The measurement was taken at the level of 2 distal scan - abutments. The scanner's precision ranges from 24 to 52  m , depending on the dist ance between scan - abutment. CS3500® (Carestream Dental LLC, Atlanta, USA) intraoral scanner has detected a valid device in the execution of complex rehabilitations on implants. His accuracy and precision values fall within the range established in li terature to define acceptable the prosthetic fitting on full arch implant rehabilitation